While the wiring is a bit messy, there's parts of it that don't seem to make too much sense:
- You open Excel, and access the ActiveWorkbook, and then open a specific workbook. Why are you accessing the ActiveWorkbook?
- You access the Sheets property of the workbook you opened, close the workbook reference, then access the Worksheets property of the Excel application. You only use the Sheets property of the workbook just to get the number of sheets. You already have the Sheets from the workbook, why do you need to access the Worksheets property of the Excel application?
To original poster: Open the Example Finder (Help->Find Examples). Change to the Search tab, and enter "Excel" in the search box. Open the example called "Excel Macro Example". In there you will find 3 VI that you need: "Open Excel and Make Visible", "Open Specific Workbook", and "Open Specific Worksheet". You should copy the VI to your working directory and use them in your code. The "Open Specific Worksheet" has a constant of "1" wired in the block diagram to always open worksheet 1. All you need to do is replace this with a control to open a specific sheet. The "Excel Macro Example" also shows you the correct order in closing the references.